Facsimile printer blade assembly



N. L. COHEN ETAL FACSIMILE PRINTER BLADE ASSEMBLY July 30, 1957 2Sheets-Sheet l Filed May 31, 1955 INVENTORS Nathaniel L. Cohen JosephTurono ATTORNE 1 July 30, 1957 N. L. COHEN EI'AL 2,801,149

FACSIMILE PRINTER BLADE ASSEMBLY Filed May 31, 1955 2 Sheets-Sheet 2INVENTORS Y K Nathaniel L. Cohen Joseph -Turuno JTI'ORNE Y United StatesPatent FACSIMILE PRINTER BLADE ASSEMBLY Nathaniel L. Cohen, New Milford,and Joseph J. Turano, Rego Park, N. Y., assignors to Air Associates,Inc., Orange, N. 1., a corporation of New Jersey Application May 31,1955, Serial No. 511,939

1 Claim. (Cl. 346-139) The present invention relates in general tofacsimile recorders of the type employing the so-called lawnmowerelectrode system in which an electrosensitive recording medium is passedbetween a substantially stationary linear electrode or printer blade anda cooperating rotating helical electrode for purposes of effectingmarking of the recording medium in response to signal intelligencetransmitted to the electrode system from a suitable facsimile scanner.More particularly, the invention contemplates the provision of animproved stationary electrode or printer blade and printer bladeassembly for use in recorders of the general class described as well asimproved methods for mounting the printer blade in operativerelationship with respect to the cooperating helical electrode.

Fundamentally, the theory of operation of facsimile transmission andrecording as well as duplication processes employing facsimileprinciples, involves the translation of subject intelligence from anoriginal copy sheet into electrical currents characteristic ofcontrasting areas of the original copy and effected by impinging lightfrom successive small areas of the copy onto a photoelectricallyresponsive device provided at the facsimile transmitter. At thereceiving or reproduction end of the system, the characteristic currentsare used to control means for reproducing the original image orintelligence, which, in the lawnmower type of recorder, is accomplishedby drawing an electrically sensitive sheet or carrier across therotating helical electrode and under the intersecting stationary linearelectrode. The intersection of the two electrodes forms a linearscanning area which owing to the helical form of the rotating electrodemoves across the paper from side to side while a steady forward movementof the recording medium between the electrodes completes the scanningmotion. The variable density markings of the original copy arereproduced by passing the characteristic currents generated at thetransmitter between the linear and helical electrodes and through theelectrically sensitive recording sheet passing therebetween.

The phenomena of marking or recording in most facsimile systems iselectrolytic in action and the density and intensity of the marksproduced on the recording sheet, among other factors, depend upon thenature of chemical reactions occurring within or upon the recordingsheet during electrolysis. Certain known sensitizing agents used inelectro-chemical wet recording papers for instance, are known to be morestable when in an acid condition. Owing to the corrosive action ofelectrosensitizing agents of this type as used in the manufacture ofsome facsimile papers as well as the general electrolytic action whichoccurs during recordation in all electrochemical wet recording systems,it is found that the linear electrode or printer blade used to effectmarking of the recording paper becomes pitted and must be replaced as astandard maintenance procedure. In fact, in one form of recording papernow employed by industry, the printer blade actually constitutes thesource of one componentof the electro-chemical marking reaction, in thatPatented July 30, 1957 it functions to supply lake-forming metal ions tothe reaction for the formation of colored dyes, with the result that theprinter blade is virtually consumed in a relatively short time andrequires relatively frequent replacement. Accordingly, it is essentialin recording mechanisms of the general class described that the printerblade be relatively simple in design and production cost and that theblade be assembled or positioned within the recorder in such manner asto permit ready access for cleaning and replacement by unskilledpersons, such, for example, as clerical personnel within an office orsimilar business establishment.

Apart from replacement considerations etc., it is essential to properfunctioning of a recorder that the printer blade be sufiiciently rigidto insure good conductive contact with respect to the recording mediumand helical electrode while at the same time it must also besufliciently flexible in a linear direction and in a directionsubstantially tangential to the surface of the recording drum to permitmounting of the blade onto the raised helix and descent from the helixfor each revolution of the drum without undue drag or wrinkling of therecording paper. In the past, these physical requirements have beenobtained or sought through rather elaborate and expensive printer bladedesigns with the result that the aforementioned replacementconsiderations involve a relatively costly maintenance factor. Inaddition, the very complexity of known blade designs introduces apotential source of operating difliculties which customarily require theattention of a skilled technician for correction or elimination.

It is the principal object of the present invention to provide afacsimile printer blade of extremely simple and inexpensive constructionthat includes within an otherwise unitary blade structure, two separateand completely interchangeable printing surfaces.

It is a further object of the invention to provide a printer bladeassembly for use on a facsimile recorder in which the printer blade isso positioned as to provide for ready accessibility for removal andreplacement by even unskilled persons.

A still further object of the invention is the provision of anadjustable facsimile printer blade mounting or holder which is sodesigned as to automatically insure a proper degree of resiliency to anexpendable or replaceable printer blade unit used in conjunctiontherewith.

The above-mentioned and other features and objects of the invention andthe manner of attaining them will become more apparent and the inventionitself will be best understood by reference to the following descriptionof a specific embodiment of the invention taken in conjunction with theaccompanying drawings, wherein:

Fig. 1 is a perspective view showing the linear electrode or printerblade of the invention disassociated from the blade holder or mountingbracket;

Fig. 2 is a plan view of the complete printer blade assembly with thelinear electrode element or printer blade of Fig. 1 in an operativeposition within the blade holder or mounting;

Fig. 3 is an elevational view of the printer blade assembly asillustrated in Fig. 2;

Fig. 4 is a cross-sectional view of the printer blade assembly takenalong the line 4-4 of Fig. 2, showing the relative positioning andmounting arrangement of the removable printer blade within the bladeholder;

Fig. 5 is a cross-sectional View of the printer blade assembly takenalong line 55 of Fig. 2, showing the tensioning arrangement employed inthe blade assembly of the invention; and

Fig. 6 is a fragmentary end view of a facsimile recorder showing theprinter blade assembly of the invention in 3 operative relationship withrespect to a recording drum and the helical electrode carried thereon.

With reference to Fig. l of the drawing, there is illustrated inperspective, the removable and replaceable linear electrode element orprinter blade 10 of the invention which consists of a simple thinmetallic strip bent at each edge to form a substantially S-shaped unitproviding two separate and interchangeable electrode surfaces 11. Theprinter blade 10 may be formed of any suitable conductive material butin practice we have found that a relatively inert alloy of steel, such,for example, as Carpenter steel, is preferred from the standpoint ofdurability. Of course, when the printer blade is employed in conjunctionwith specific electro-sensitizing agents, the actual electrode surfacesor edges of the blade may be plated or coated with any suitable metallicsubstance or alloy to provide for increased resistance against corrosionand electrolytic decomposition or to provide a source of reactivematerial necessary to the electrochemical marking phenomenon.

With reference to Figs. 2 and 3 of the drawings, the printer blademounting assembly of the invention consists of an elongated metallicframe or channel member 12 closed on three sides and having mountedthereon at each end by means of retaining bolts 13, a blade-retainerpiece 14. As best seen by reference to Fig. 4, the metallic frame 12 andblade-retainer pieces 14 mounted at each end thereof, define twosubstantially closed channel sections into which printer blade 10 isreceived by sliding from a single substantially open end provided at oneend of the frame. Thus, one end (upper end Figs. 2 and 3) of frame 12 isprovided With a relatively extended stop abutment piece 15 whichisadapted to contact the end of the printer blade when it is fullyreceived within the frame to prevent any movement of the blade beyondthis end of the frame, whereasat the opposite end offrame 12 (lower endFigs. 2 and 3) a relatively low abutment or lip 16 is formed integralwith the frame and is adapted to permit insertion of the blade by simplysliding it over the lip until the blade is fully inserted. in the :frameat which point the edge of the blade drops below the lip therebysecuring the blade against movement in either direction within the frameduring theprinting operation. To remove a blade for reversal ofitselectrode edges or complete replacement, it is simply necessary tolift the end of the blade slightly to clear abutment 16 and then slidethe blade out over theabutment.

Again with reference to Fig. 4, it will be seen tha printer blade 10 isretained within the channel sections formed by frame 12 andblade-retainer pieces 14 in a freely pivotal position for movement:about the fulcrum point indicated by reference numeral 17 .in Fig. 4.Accordingly, any force applied against the operative electrode surfaceof the blade, such as that encountered when the blade rises and fallsfrom the .helical. electrode at i the beginning and end of eachrevolution of the recorder drum, willbe absorbed by a simple pivotalmotion of the blade within the frame. In order to insure good conductivecontact at all times, the aforedescribed motion of the linear electrodeis resiliently restrained by :means of a butterfly spring 13 (Fig.5)which is centrallyanchored on frame 12 by means of nut andbolt assembly19. Spring 18 is provided with a clip extension20 at the end of eachleaf thereof which areradapted to engage the forward angled edge ofprinter blade10 thereby tensioningthe blade bothinwardly and downwardly.Upon removing a blade, the clip extensions 20 are simplylifted out fromthe edge of the blade-and permitted to extend freely below the bottom offrame 12 until a blade is reinserted in the frame and the clips are thenrepositioned thereon, as best seen by reference to Fig. 5.

At the ends of frame 12 and also'secured to the frame by retaining bolts13, weprovide a pair of,.channel blocks ings, channel blocks 21 areadapted to be received within channels 22 provided in a pair of rockerarms 23 pivotally suspended from each side of the recorder in the mannerdescribed in our copending United States application Serial No. 569,868which Was filed on March 6, 1956, entitled Facsimile Recorder. Channelblocks 21 are eachprovided with a seating hole 24 which is adapted toreceive a tensioning spring 25. Below the springv seatings 24, thechannel blocks 21 are tapped as indicated by reference numeral 26 inFig. 6 to engage a knurled adjustment bolt 27 which extends throughholes 28 provided in the rocker arms 23. In this manner, the positioningand pressure of the printer blade with respect to the record sheet andhelical electrode 29 can be adjusted by a simple adjustment of bolts 27while the machine is in operation, thereby insuring optimum quality ofcopy under various operating conditions.

Referring to Fig. 6, reference numeral 30 represents a recording drumcarrying the conventional helical electrode 29. vIn order to avoidstrain on printer blade 10 resulting from tension within the recordingpaper, which has been indicated by reference numeral 31 in Fig. 6, andto insure that the paper is presented to the electrode system (10-29) ina plane substantially perpendicular to the current path through theelectrodes, we provide a paper guide strip 32 on frame 12. Paper guide32, which may be formed of any suitable non-conductible materiahisriveted or otherwise secured to frame 12 and extends completely acrossthe frame as best seen by reference to Fig. 2.

.As the paper is fed under the opposed electrodes, paper guide-.32serves to absorb any shock or tension within the paper that mightotherwise result in fluttering or vibration of .the linear electrode 10and also positions the paper tangentially to the surface of recorderdrum 30 and helical electrode 29 carried thereon. The guide isadjustably positioned by the same adjustment bolts 27 whichcontrol thepositioning or pressure of printer blade 10.

Any suitable connection can be used to complete the electrical circuitfrom the helical electrode, such, for example, as a wire lead solderedto frame 12 or secured thereto with a conventionallug connector at nutand bolt assembly 19.

While we have describedabove the principles of our invention inconnection with a specific embodiment thereof, it is to be clearlyunderstood that this description is made only by way of illustration andnot as any limitation with respect to the scope of our invention asdefined within the following claim.

We claim:

In a facsimile recorder of the type employing a substantially stationarylinear electrode and a cooperating rotating helical electrode carried ona cylindrical recorder drum, a linear electrode assembly comprising aremovable printer blade having two identical linear electrode surfacestformed thereon which are selectively engageable with the helicalelectrode, a supporting frame for said printer blade electrode includingmeans for pivotally securing said blade therein, means mounted on saidframe and positioned to engage said printer blade for resilientlytensioning the blade against pivotal motion within said frame, and apaper guide element secured to said supporting frame immediatelyadjacent said printer blade and positioned to guide a facsimilerecording sheet into contact with an electrode surface of saidprinterblade in a plane tangential to the surfaceof the cylindrical recorderdrum carrying the helical electrode.

References Qitcd in the file of this patent UNITED STATES PATENTS2,515,864 Finch et al July 18, 1950 2,540,080 Alden Feb. 6, 19512,728,627 Alden Dec. 27, 1955

